Dam



y 1937- s. w. STEWART ET AL 2,080,637

DAM

e snets-sh'eet 1 Filed Feb. 10, 1934 M ATTORN v blTons May 18, 1937. s. w. STEWART ET AL DAM Fild Feb. 10, 1954 6 Sheets-Shet 2 INQIENTORS My Q4ZQ Z? ATTOR May 18, 1937.

S. W. STEWART ET AL DAM Filed Feb. 10, 1954 6 Sheets-Sheet 3 5.? 36 13 2.9 y r A z /H 0 n N INVENTO s ATTOR YS May 18, 1937. s. w. STEWART. ET AL 2,030,637

DAM

Filed Feb. 10, 1934 6 Sheets-Sheet 4 INVENTORJ BY 97$ L AT'II'ORNEYK y 1 s. w. STEWART ET AL 2,080,637

DAM

Filed Feb. 10, 1964 6 Sheets-Sheet 5 INVENTOR5 4 7/ l I 3 BY ATTORNEY;

May- 18, 1937. s. w. STEWART ET AL ,0

DAM

Filed Feb. 10, 1934 6 Sheets-Sheet 6 INVENTOE 5 7% BY yw 44/ ATToRNEy Patented May 18, 1937 6 UNITED STATES PATET OFFICE DAM Spencer W.

Stewart, White Plains, N. Y., and

Application February 10, 1934, Serial No. 710,590

15 Claims.

This invention relates to a novel and improved form of dam and to a novel method of constructing portions thereof. The novel features will be best understood from the following description and the annexed drawings, in which are shown selected embodiments of the dams constructed according to the invention, and in which:

Fig. 1 is a vertical cross sectional view through a dam constructed according to one embodiment of the invention and taken on the line of Fig. 2.

Fig. 2 is a view of the dam shown in Fig. 1 as viewed from the down-stream face thereof.

'15 Fig. 3 is a section on the line 3-3 of Fig. 1.

Fig. 4 is a section taken on the same plane as Fig. 3, but showing a different embodiment of the invention.

Figs. 5 and 6 are views corresponding to Figs. 3 and 4, but showing forms of the invention particularly adapted for use with a different type of abutment from the type shown in Figs. 3 and 4..

Figs. 7 and 8 are views similar to Figs. 3, 4, 5, and 6, showing still other forms which the invention may take.

Fig. 9 is a view taken on the same plane as Fig. l, but on an enlarged scale and showing certain details of construction.

Fig. 10 is an enlarged cross sectional view showing a detail of construction of one of the drains.

Figs. ll, 12, and 13 are views taken on the same plane as Figs. 5 and 6 and showing a novel method of building a structure shown in those figures.

Fig. 14 is a detail view of part of the structure appearing in Fig. 11, but on an enlarged scale.

This invention relates particularly to the type of dam in which an up-stream inclined waterbearing deck is supported upon a plurality of buttresses disposed beneath the deck and extending down-stream therefrom. In prior art practice, it has been customary to form the waterbearing deck of slabs or arches supported on the buttresses and spanning the spaces therebetween. A suitable joint has been provided between the slabs or arches and the buttresses upon which they rest, both upon the bearing surfaces and at other contacting surfaces. These joints have generally been sufficiently water-tight, particularly with dams which are relatively low and which are built upon stable foundations which are not subject to disturbance. In the construction of relatively high dams, however, and/or dams which are likely to be subjected to earthquakes or to displacement from other causes, there is the danger that these joints will not be sufficient to prevent passage of water therethrough to a sufiicient degree to cause failure of the dam or the disintegration of the slabs.

According to our invention, we provide a dam such as shown in Figs. 1, 2, and 3, for example, in which there are provided buttresses .l as in the prior art, these buttresses being spaced apart as usual but being of a different construction adjacent their up-stream edges. As plainly shown in Fig. 3, each up-stream edge is provided with gradually flaring portions which may be formed by tangents or by curves 2 of long radius so as to provide heads 3 of substantial thickness at the up-stream edge portions of the buttresses. These heads 3 support a plurality of structural members, here shown as two in number and designated 4 and 5, respectively. These members are shown as slabs resting upon bearings 6 and 1, respectively, and having tongue and groove joints 8 and 9 with the up-stream edge portions H) of the buttresses, which portions are disposed between adjacent ends of slabs placed on opposite sides thereof. The slabs 4 and 5 may be supplied with any usual and suitable reinforcement l I, if that is found desirable.

The joints 8 and 9 and the bearings 6 and 'l are formed of contacting surfaces which are preferably painted with asphalt or some other suitable material, so as to prevent any bond therebetween and to permit independent movement of the relative parts. The joints 8 and 9 at the right-hand end of the slabs shown in Fig.3 are shown as expansion joints packed with asphalt or other suitable material which will resist the passage of water while permitting relative movement lengthwise of the dam. Such joints will, of course, be provided at suitable intervals.

The bearing surfaces 6 and l are shown as inclined to the up-stream water-bearing surface [2 and are formed upon the head which is, in turn, formed by the gradual flaring out of the buttress. By this gradual flaring, the lines of pressure exerted on the bearings are more smoothly and uniformly distributed and, in fact, are distributed over the entire section 'of the head and in such a way as to cause all stresses to be compressive stresses rather than tensional. This arrangement adds very greatly to the safety of the entire dam.

The members 4 and 5 are designed to act separately, and their adjacent surfaces preferably contact as indicated at 13, these contacting surfaces preferably being painted with asphalt or some other suitable material which will prevent a bond between the two members. An alternate method would be to insert sheets of asphaltic or other suitable waterproofing material between the surfaces of the concrete members. Along the contacting surfaces are provided suitable drains which may be formed by recesses 14 in one member, these recesses extending parallel to the contacting surfaces, and preferably communicating drains l5 are provided which lead from the recesses to the down-stream face I6 of the deck. Preferably also, each member 4 and 5 is designed to take the entire load placed upon it by the water which the dam impounds, inthe same manner as if there were only one such member spanning the space between adjacent buttresses.

By the above construction, numerous advantages are obtained, among which may be men tioned the fact that the factor of safety of the dam as a whole is practically doubled, because if one structural member should fail, the other would still be able to take the load put upon it by the water. This additional safety is achieved at a relatively small cost of material and labor.

Assuming that water should work through a joint 8, before it could reach the down-stream face of the deck it would have to pass along the bearing surface 6, through the joint 9, and along the bearing surface 1. Even though an earthquake or other disturbance should cause a pulling away of a slab or other structural member from the adjacent buttresses enough to open up the joints 8 and 9, nevertheless there is still present a large extent of bearing surface 6 and 1 through which the water must find its way, and since the water itself is pressing the structural members against these surfaces, it will be readily seen that the danger of failure from this cause is greatly decreased. Moreover, water finding its way past or through a member 4 may be taken care of by the drains I 4 and I5, and thus hydrostatic pressure will not be built up within the deck. In other words, the down-stream member'5 may be left largely as an emergency member.

Other advantages than those enumerated above will be apparent to those skilled in the art, and it is not deemed necessary to discuss them here.

In Fig. 4 is shown a different form of the invention wherein the deck is formed of four structural members IT, IS, l9, and 20. In this form, the members are shown as slabs as before, although for the sake of simplicity the reinforcement has been omitted therefrom, it being understood that suitable reinforcement may be used in the construction shown in any figures of the drawings where it is found desirable. Drains 2| and 22 corresponding to the drains I4 and I5 of Fig. 3 are also shown, although in this form the two up-stream members I! and [8 have no drain therebetween. It will be understood, of course, that under some'conditions the drains may be omitted entirely, although preferably they are used. Drains 23 are also shown in both Figs. 3

and 4 extending lengthwise through the heads 3 effects of shrinkage and temperature. Joints such as 10 and H, Fig. 4, may be necessary to relieve these temperature and shrinkage stresses and prevent cracking. These joints are particularly adaptable to all the flexible and laminated slab construction as disclosed by this application, owing to the fact that the resultant thrusts of each Water bearing slab are directed inwardly tawards the buttress, thus putting the joints under compression.

Referring first to Fig. 5, it will be seen that the members 25 and 26 are in the form of arches instead of slabs. The arch 26 rests upon abutments 21 on the buttresses, and is preferably so designed as to carry the load of the Water above it. The member 25 also has abutments 28 on the buttresses, but it also has surfaces 29 engaging surfaces on the adjacent up-stream edge portions of the buttresses and extending up-stream and down-stream, whereby the member 25 can be used as a brace, thereby overcoming certain disadvantages of the use of an arch in a deck of a dam of this type. At the same time, certain disadvantages of a slab are avoided. In other words, the construction shown combines advantageous features of both the arch and the slab and avoids their disadvantages. The member 25 is designed not only as a brace, but preferably as an arch of sufficient strength to bear the load of the water, without aid from the arch 26.

The arches 25 and 26 contact along a surface indicated at 30, and this surface is preferably painted with asphalt or the like so as to prevent the two arches forming a bond therebetween. Thus, each arch can function independently of the other. Drains 3| are likewise provided along this surface 30, and communicating drains 32 may be likewise provided leading from the drains 3| to the down-stream face of the deck.

The up-stream surface 33 of the deck is preferably flush with the up-stream edges 34 of the buttresses, although some advantages would be obtained by making theup-stream buttress face action of the arch 25, we preferably provide open- I ings 35 extending down-stream from the surface 33 to a point approximately at the theoretical extrados of the arch. These openings may be conveniently filled with some metallic, fibrous or other suitable material to break the bond between the parts of the concrete on opposite sides thereof so as to prevent those parts acting together and thus interfering with thearch action of the rest of the member.

Under normal conditions, both arches 25 and 26 willdivide the load of the water between them, whereas the arch 25 will act as a brace between adjacent buttresses, which is of particular advantage in case of an earthquake or any other disturbance. The two arches acting independ ently of each other make a flexible arrangement, and one in which stresses are minimized.

The arches may be built in sections separated by construction joints 36, and the drains 3| are preferably placed at these joints and are preferably of a construction shown in Fig. 10 and which will be more fully described presently.

The bracing action may be increased quite materially by the construction shown in Fig. 6, wherein we have shown arches 31 and 38 corresponding generally to the arches 25 and 26, but in which the intrados of the arch 31 and the extrados of the arch38 are stepped as indicated to form steps 39 extending up-stream and downstream and coacting to prevent relative lateral displacement or, in other words, displacement lengthwise of the dam. Similarly, the extrados of the arch 38 may be provided with a step 40 engaging the adjacent buttress 24. In other respects, this form follows closely that in Fig. 5, and will not be further described.

In Fig. '7 is shown still another form of the invention in which are used buttresses 4| of the type generally used in the prior art, and having haunches 42 upon which are provided bearings for the deck. In this form, these bearings 43 are used as abutments for a combination arch and brace 44, which may be provided with suitable reinforcement 45. Above the arch 44 is a second structural member 46 having its down-stream. surface contacting with the extrados of the arch 44, but designed to' act as 'a combination beam or slab and brace. This also may be provided with suitable reinforcement 41. In this form, as in the others, each one of the structural members is designed to act independently of the others and to take substantially the entire load of the water, so that each member can carry that load in the absence of the other.

In Fig. 8 is shown a form similar to that of Fig. 3, except that here the buttresses are similar to those designated 24 in connection with the description of Figs. and 6. In other words, these buttresses are of the massive type having a gravity cross-section of the type described in said copending application. The up-stream. faces of these buttresses may be either vertical or inclined. The structural members 5 and 6' are similar to those described in connection with Fig. 3, and further detailed description thereof will not be given.

Where a reservoir is not maintained full, the dam, of course, is sometimes under only partial load and exposed to the atmosphere. Where there are wide ranges in the atmospheric temperature, this of course means that a substantial amount of expansion and contraction will tend to take place in the exposed deck. The underside of the deck of course is shaded and cooler than the up-stream side, and therefore a differential in temperature occurs which will set up stresses which may be of substantial amount. The type of deck described herein is obviously of advantage in such circumstances, because the up-stream member may expand and contract independently of the down-stream member or members.

As a further precaution, the structural members, particularly the one furthest up-stream and designated 48 in Fig. 9, may be provided with expansion joints 49 extending lengthwise of the dam. These construction joints may be of the tongue and groove type illustrated, or of any other suitable construction, and serve to localize the expansion and contraction. This arrangement would not be feasible with a single structural member forming a deck because of the danger of leakage therethrough. However, with the arrangement described in this application, such joints can be used with safety, because any water which might find its way through a joint 49 will be stopped by the next lower structural member 55. This member may be likewise provided with expansion joints 5| therein, these joints being staggered with respect to the joints 49 and likewise extending lengthwise of the dam. In order to relieve any hydrostatic pressure which might otherwise build up between the two members 48 and 5!], suitable drains 52 are provided through the member 50.

In Fig. 9 we have also shown an arrangement for preventing relative movement between adjacent sections of the member 48. In that figure, we have shown a fragmentary portion of a surface 53 of the member 48, this surface, for example, forming the joint 8 of Fig. 3 or similar joints, such as shown in the other figures. This joint may include grooves 54 extending lengthwise of the member 48 and connecting with cross grooves 55, in which grooves are received corresponding projections on the adjacent buttress. Similarly, the grooves may be formed in the adjacent face of the buttress and the projections formed on the structural member, in the manner described and claimed 'in the patent of Edgar H. Burroughs, No. 1,864,976. This construction ties together adjacent buttresses and structural members spanning the spaces therebetween, while permitting limited relative movement lengthwise of the deck. This limited movement is localized and has no opportunity to build up to such an amount as to become dangerous. In a dam of any substantial height subjected to extreme differences in temperature, the amount might be sufficient to add greatly to the danger of overturning, but such danger is avoided by the construction shown.

Referring now to Fig. 10, we have shown therein a form of construction which may be conveniently used with several of the embodiments of dam shown herein. For the sake of simplicity, we will refer to the form of construction shown in Fig. 5, although a similar construction may be used in other places where found applicable.

The drain shown in Fig. 10 may be used in place of the drain indicated at 3| in Fig. 5, in the form of a square recess, and is preferably located at a joint which, for the sake of convenience, we will consider to be one of the joints 36 shown in Fig. 5. The drain 56 is shown as cylindrical in form and is made of a single piece of sheet metal flashing 51 which may be bent into the generally cylindrical form shown. The flashing is provided with two folds 58 and 59 connecting the cylindrical portion of the drain to wings 60 and.

6|, embedded in the concrete on opposite sides of the joint 36. The two folds are overlapped at the joint 36 so that any water coming through the joint 36 may pass through the joint in the drain formed between these two folds. The lower portion of the drain is placed substantially in contact with the surface 3|] dividing the two arches or other structural members.

By the above arrangement, any moisture seeping through the joint 36 will find its way into the drain as noted above, while at the same time the portions of the masonry on opposite sides of the joint 36 may move relatively to each other, without disturbing the drain. During this movement the two folds may slide on each other enough to take up that movement, without opening up the drain. At the same time, the passage of water is resisted by the pressure exerted on each other by the two folds, but of course the drain will take care of what little water may seep through.

Turning now to Figs. 1 1, 12, and 13, we have shown therein a novel method of forming a plurality of structural members, such as arches arranged as described above. For the purposes of illustration, we have assumed that the buttresses 24 are of the gravity type, although that is not essential. We have also assumed that the structural members are the arches such as shown in Fig. 5, although here again the method may beapplied to other .forms of the invention where found applicable.

Referring first to Fig. 11, we prefer to first build the down-stream arch 26, supporting it upon suitable falsework 62. During the pouring of the concrete, the bolts 63 are placed in position somewhat as shown, having ends projecting through and beyond the extrados. The arch 26 may then be used as a form upon which to pour theconcrete of the structural member 25 forming the combined arch and brace in this embodiment, and a space 3| is left to form a drain .as previously described. Before pouring the concrete of the member 25, however, a nut 64 is threaded on to the end of each bolt 63, and this nut in turn is threaded to a bolt 65 of such length as to extend to the up-stream face of'the member 25, where it may be threaded into a tapered nut'66.

After both the structural members have been thus poured, and when" the forms are removed, both bolts 63 and 65 may be removed by turning them out of the nut 64. This nut will drop down the drain 3|v and may be recovered at the bottom thereof. The holes for the bolts 65 may be grouted to present a tight water-bearing surface, while the holes for the bolts 63 may be left open to'ser've as the drains indicated at 32 in Fig. 5.-

' If desired, a similar arrangement may be used, but reversing the order of pouring the arches, such" an arrangement being shown in Figs. 12 and 13, wherein Fig. 12 indicates the falsework 61 supporting the member 25 with the recesses forming the drains 3| therein. While this is being poured, the bolts 65 are placed in position with the nuts 64 thereon. The falsework is supported upon blocks 68 engaging the abutments 21, and after the concrete has set in the member25, these blocks may be knocked out and the falsework dropped to the position shown in Fig. 13, where it may be used for the intrados of the member 26., In this position it may be supported upon the bolts 63 as indicated in Fig. 13, these bolts being extended downwardly a sufficient distance to engage nuts 69 which help in holding the falsework in place. The various bolts 63 and '65 may be used where needed to support the falsework.

While we have'shown the invention as embodied in specific forms, it is to be understood that various changes in. details may be made without departing from the scope of the invention, and we therefore do not intend to limit ourselves except by the appended claims.

We claim:

g 1. In a dam, a plurality of buttresses extending .up-stream and down-stream, and a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of arches disposed one beneath the other and each spanning the space between said two buttresses and acting substantially independently of each other, separate bearings on said buttresses for said arches, and each arch and its bearings having sufficient structural strength to carry the entire load on the portion of the deck spanned thereby.

2. In a dam, a plurality of buttresses extending up-stream and down-stream, ,a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, and separate bearings on the buttresses for said members.

3. In a dam, a plurality of buttresses extending up-stream and down-stream, and a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other, said buttresses being stepped to form separate bearings for said members. v

4. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the upstream edges of said buttresses,

said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, and separate bearings on the buttresses for said members, the upstream edge of a buttress extending between the ends of all the members on opposite sides thereof.

5. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a. plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other and drains disposed between said members and substantially parallel to said surfaces.

6. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacentsurfaces of said members substantially contacting with each other, drains disposed between said members and substantially parallel to said surfaces, and otherdrains leading from said first-named drains to the down-stream face of the deck.

' 7. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two. buttresses, said buttresses being stepped to form separate bearings for said members, each of said bearings being inclined up-stream away from their outer edges, and the buttresses being gradually flared outwardly to said bearings.

8. In a dam, a plurality of buttresses extending ing up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said an arch and the other engaging the adjacent buttresses along surfaces extending up-stream and down-stream to brace said buttresses.

9. In a dam, a plurality of buttresses extending up-stream and down-stream, and a waterbearing deck at the up-stream edges of said buttresses,- said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other, one of said members being in the form of an arch and the other in the form of a beam and each engaging the adjacent buttresses along surfaces extending up-stream and down-stream to brace said buttresses.

10. In a dam, a plurality of buttresses extending up-stream and down-stream, and a waterbearing .deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of structural members spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other and each having portions extending up-stream and down-stream and engaging each other to prevent relative movement therebetween lengthwise of the dam.

11. In a dam, a plurality of buttresses extending up-stream and down-stream, and a waterbearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous arches spanning the space between said two buttresses, with the adjacent surfaces of said arches substantially contacting with each other and having portions extending up-stream and down-stream and engaging each other to prevent relative movement therebetween lengthwise of the dam.

12. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of. arches spanning the space between said two buttresses, with the adjacent surfaces of said arches substantially contacting with each other, the arch furthest up-stream having a water-bearing surface beyond the theoretical extrados of the arch, and joints leading from said bearing surface approximately to said theoretical extrados.

13. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other, and expansion joints in said members extending lengthwise of the dam, the joints in one member being staggered with relation to those in adjacent members.

14. In a dam, a plurality of buttresses extending up-stream and down-stream, a water-bearing deck at the up-stream edges of said buttresses, said deck between two adjacent buttresses comprising a plurality of continuous water-tight structural members disposed one beneath the other and each spanning the space between said two buttresses, with the adjacent surfaces of said members substantially contacting with each other, expansion joints in said members extending lengthwise of the dam, the joints in one member being staggered with relation to those in adjacent members, and drains leading from said contacting surfaces to the down-stream face of the deck.

15. The method of constructing a masonry arch having spaced buttresses and a plurality of structural members spanning the space between two of said buttresses and contacting with each other, which comprises building one of said members and disposing a bolt therethrough having an end projecting therefrom on the side adjacent another of said members, placing a nut on said projecting end of the bolt, threading a second bolt into said nut, building said other member around said second bolt, and removing one of said bolts by turning it out of said nut, whereby the hole formerly occupied by the bolt acts as a drain.

SPENCER W. STEWART. CALVIN V. DAVIS. 

